


Dust, Sweat, and Tears

by snassty



Category: Undertale (Video Game)
Genre: Angst, Ecto-Genitalia, Eye Sex, Hurt/Comfort, M/M, Masturbation, Physical Abuse, Red has a horrible past, Referenced past abuse, Somewhat established relationship, Soul Sex, Unhealthy BDSM Etiquette, bone touching, cool bro Papyrus, soul dynamics, the fontcest is largely one-sided
Language: English
Status: In-Progress
Published: 2016-06-10
Updated: 2016-09-18
Packaged: 2018-07-14 07:51:17
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 8
Words: 10,110
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7161239
Author URL: https://archiveofourown.org/users/snassty/pseuds/snassty
Summary: <blockquote class="userstuff">
              <p>(lame title is lame)</p>
<p>Underfell Sans narrowly avoids being killed, escaping to the only place he can even remotely call "home." He begins to grow very close to this universe's version of himself -- and maybe even begins to heal from old wounds.</p>
<p>(Basically just really grossly self-indulgent Bled. Don't judge me)</p>
            </blockquote>





	1. Chapter 1

"COME BACK HERE, YOU WORTHLESS PIECE OF GARBAGE!"

A frighteningly recognizable snarl echoed through Snowdin Forest and into the town's entrance, causing overhearing monsters to peek out for any sign of the source of The Great And Terrible Papyrus' wrath. A scramble of snow and a muttered litany of curses indicated the poor bastard's arrival.

"shitfuck shit shit sshhiiiit fuckfuckfuck!"

Sans wasn't even aware he could move that fast, but somehow Boss always brought out the best in him. Worst? Most anxiety-ridden, in any case. Sans narrowly avoided a flurry of sharpened bones that came flying at him from behind. His entire body was shaking violently, making escaping Papyrus nothing if not damn near impossible. He whimpered as he gathered all of his magic energy.

There was only one place he could call "safe." One place he knew Boss would never be able to follow him to. He'd only been there once before, by complete accident, and he wasn't entirely sure he could even get back there -- but damn if he wasn't going to try. He forced himself to focus on the cozy little house in Snowdin -- a very different Snowdin -- and as he reached out to tug himself away, he kicked up a flurry of snowflakes, leaving Underfell behind.


	2. Chapter 2

**Summary for the Chapter:**

> Someone shows up in the Undertale universe... but apparently, this isn't the first time it's happened.

**Notes for the Chapter:**

> It should be fairly clear what universe each chapter takes place in. Also, please heed the warning that this is EXTREMELY SELF-INDULGENT

A loud 'thud' in the living room seized the skeleton brothers' attention away from dinner. Papyrus whipped his head around toward the source of the noise, a lone noodle dangling from his teeth, flinging a bit of sauce. Sans would have found this funny if the sudden presence in the adjacent room hadn't dropped a weight in his non-existent gut. He was on his feet in an instant, halfway across the kitchen before he even realized he'd started moving.

"red," he gasped, collapsing on his knees beside the skeleton who could easily pass for his identical twin. 'Red' was on all fours, trembling, ribs heaving as he gulped in air, desperately wanting to calm down after what he was sure was a near-dust experience. Wisps of magic flared and trailed weakly from his eye; remnants of the energy he'd exerted to teleport clear into another dimension.

"hey, it's alright. you're safe." Sans placed a gentle hand on Red's skull, earning a shaky nuzzle into the small offer of comfort. He was the only person who could touch Red like this -- could touch him at all, really. Papyrus, bless him, had tried numerous times to embrace Red, and only succeeded once, which had sent his brother's double into a fit of panic. Papyrus hadn't tried to initiate contact again after that. He didn't know why Red had reacted the way he had, but he didn't want to cause it again.

Sans, however, knew exactly why. And he figured it was the same reason why his alternate self was now cowering on his living room floor. "pap, can you go make sure there's sheets on my bed?"

"Of course, brother," Papyrus answered, his voice lacking its usual exuberance (he'd discovered, when they'd first met Red, that speaking more softly didn't seem to startle him as much). He swiftly made his way up the stairs and into Sans' bedroom.

"hey, sweetheart," Sans cooed, turning back to the shivering skeleton before him.

"d-don't fuckin' call me that." Despite his words of protest, Red's tone was gentle. Sans knew he was smiling.

"can you sit up for me?" Sans prompted. Red grunted softly and shifted to sit on his knees. "there we go. there's that cute face." He curled his hand over Red's cheek.

"shut up," Red mumbled, though he leaned into Sans' metacarpals, his sockets half-lidded.

Sans' smile softened as he swiped his thumb across the dark circle under Red's eyesocket. He loved being able to calm his twin like this, loved seeing him melt under his gentle touch. He already knew Red was starved for affection. It felt so nice to be the one to give it to him.

When Papyrus burst out of the door and announced that Sans' room was fit to receive company, Sans got to his feet and extended a hand to help Red do the same. Their magical energies sparked pleasantly at the contact. Red gripped his double's hand tightly as Sans led him up the stairs to his bedroom.

Once they were in the room with the door closed, Red plopped his tailbone down on the edge of the bed with a shuddering sigh.

"boss again?" Sans murmured.

Red nodded curtly. "tried to dust me," he choked. "a-almost succeeded."

"i'm glad he didn't." Standing in front of Red, Sans bent down to touch a skeleton kiss to the top of his skull. "glad you made it here." A few moments passed in silence as Sans sat beside Red, the mattress dipping slightly with his added weight. He lifted a hand and brushed his knuckles down Red's cheekbone. "i've missed you," he breathed.

"m-me too." Red's reaction was instant. "fuck, blue, i've missed you so fuckin' much." His eyes fluttered open and he gazed at Sans with an expression not unlike a lovestruck puppy.

Sans' Soul pulsed. He thought back to the last time he'd seen Red; the incident that had caused them to meet. Red had appeared in their house, just like this time, but it had been an accident, likely caused by the alcohol in his system confusing his magic. Sans had learned a lot about his double and the world he came from, and Red had trusted him almost immediately. He'd let Sans close enough to inspect his injuries, even heal them. Close enough to touch him in that soothing, unhurried way of his. And, on one occasion, even close enough to share a kiss with him. It had been brief, and chaste, and a little awkward, and Sans hadn't attempted it again, but ever since, their relationship had been a little... hard to figure out.

Sans gave him a gentle smile and continued to stroke his skull, his free hand moving to slide Red's jacket off his shoulders. He trailed his touch along the other's clavicle, his movements pausing when he reached the collar fastened around his counterpart's neck. Red met his gaze, only to find that the lights in Sans' sockets had disappeared, and his mouth had twisted into an ugly snarl.

For the first time since meeting his alternate self, Red was afraid of him. "b-blue?" he cowered.

"You're not going back," Sans growled, his voice eerily serious. "I don't care what happens to that universe. I'm not fucking letting you go back there."

"w-why not?" Red asked, curiously rather than defiantly.

Sans gripped the small gold tag so hard it bent slightly. "you don't belong to anyone," he hissed. "especially not that sick fuck."

"that's where you're wrong, bluey," Red murmured with a dry chuckle. As Sans' head snapped up to look him in the face, Red wrapped trembling fingers around Sans' hand. "y'see... i belong to you." He lifted his gaze to meet his twin's, and Sans made a small noise of surprise -- Red quite literally had hearts in his eyes. "i'm yours."

"kiddo," Sans whispered, his own eyelights reshaping to mirror his double's expression.

Red flushed and chewed what served as his lower lip, the tiny hearts in his sockets swimming hazily. He tilted his chin up slightly as Sans turned the collar around and began to fiddle with the clasp. "i-it's locked shut," he supplied.

"mmh." Sans frowned, extending tiny tendrils of magic from his fingers to prod at the mechanism. "i don't care. i'll cut it off if i have to."

"i don't... really mind it," Red lied. Physically, at least, he'd grown accustomed to the collar's presence. Psychologically, though, he resented the reminder that he was essentially his brother's bitch.

"i do." Sans gave a tiny 'ah!' of victory as his magic picked the lock, and he whisked it from around Red's neck. Upon getting a closer look at it, though, his anger returned. In addition to the gold studs around the outside, the collar also had small spikes pointed inward. The finish on the inner spikes was worn off -- Sans looked back up to Red's cervical vertebrae and found them littered with scrapes and punctures. He shuddered with rage.

"you are not his fucking pet," he snarled, flinging the collar across the room.

Red absently touched his neck where the collar had been. "i'm more of a toy, really," he muttered. "something to play with when he's bored. something to break again and again."

Sans' fingers, humming with soothing magic, joined Red's at his throat. "you don't deserve that."

"i don't deserve you."

"babe, you deserve all the best things the world has to offer."

Red shivered pleasantly at the petname and craned his neck into his twin's touch.

"hmm?" Sans gave a soft chuckle of amusement. "you really do like when i call you those things, don'tcha?"

"s' better than 'asshole'." Red's socket-lids closed as Sans' hand trailed up his throat to his lower mandible. "or 'disgrace,' or 'piece of shit,' or 'useless garbage,' or -- whatever else boss comes up with to throw at me."

Sans tilted Red's skull to tap his mouth against the other's cheek. "i don't think any of those suit you," he cooed, gently scraping his closed teeth along Red's jawline.

"yeah?" Red actually cracked a smile at that, blushing more than a little. "you got any better ideas?" he nudged coyly, draping his arms around the other, his hands coming to rest at the back of Sans' lowest ribs.

"i can think of a few, yeah." Sans hummed softly as he hooked his fingers in the fabric at Red's chest. "sweetheart." He began to kiss a languid trail up the opposite side of Red's jaw. "my literal other half." Kiss. "you absolutely," kiss, "wonderful," kiss, "adorable," kiss, "incredible," kiss kiss kiss, "treasure." One last kiss for emphasis.

Red made a single, hushed, desperate sound before gripping Sans' back tightly and clacking his teeth against his double's. He felt their auras spark with the contact, and he fed his magic into it, prompting Sans to reciprocate with a small grunt. Red pressed even closer and ground his teeth against Sans' before pulling himself back like a magnet uncoupling from its mate.

A deep flush colored both of their faces -- Sans, a cool, royal blue; Red, a fiery splash of magic the same crimson as his namesake. They gazed into each other's eyes for a long, long moment, heart-shaped lights pulsing eagerly.

"holy shit." It was Red who spoke first, his voice quiet with awe. "if -- if we're twins, basically..." Trembling phalanges lifted to ghost across Sans' mouth. "am... am i this fucking -- gorgeous?"

"do you need me to prove it to you?" Sans murmured a little more huskily than intended, dragging a hand down Red's chest.

"f-fuck, i -- yeah." Red arched into his caress and whined softly as Sans' hands slid under the hem of his shirt. "you're so -- gentle," he breathed, letting his twin pull the fabric up over his head.

"you've been hurt a lot," Sans replied simply, stripping off his own shirt.

"i-i know." Red shivered as their bare ribcages pressed together. "it's just. y'know." He bowed his head in shame. "m' not... really used to being touched like this. all i've ever known is, is -- boss' r-rough handling. having to ask permission for anything that'd make me feel good. rarely ever getting it."

Sans nudged his teeth against Red's. "tell me what you want," he purred -- not as a command, not as a lustful desire, but as a patient request.

Red absolutely melted. He let out a shuddering sigh, went nearly limp in Sans' arms, and melted into his embrace. "a-all i want," he whimpered, "is everything you're willing to give me..."

Sans nuzzled against his counterpart's forehead. "i'm willing to give you all of the love in my soul." His distal phalanges danced across Red's clavicle. "in any way i can give it to you, every possible way i can make you feel exactly how much i adore you." He touched a brief kiss to Red's mouth. "is that what you want, sans?" He surprised not only his double, but also himself, by addressing Red with the name they both shared.

"n-not... not entirely." Red's fingertips lightly caressed Sans' shoulders. "i... a-as much as i don't really think i know how to..." He blushed deeply. "i wanna love you back."

"you'll do just fine, babe." Sans smiled warmly and flicked a spark of magic towards his lamp, turning it off. "you're already doing such a good job."

"i-i am?" Red's glowing flush served as enough of a light source for them to slip off their shoes and socks and crawl under the covers. "really?"

"of course." Sans pulled the blanket up over them both as they scooched closer to accommodate for the size of the mattress. "look at you," he breathed as he stroked the back of Red's skull. "snuggling up to me like a sweet little kitten..." He chuckled fondly and kissed his forehead. "you're just a big ol' cuddle bug, aren'tcha?" Red grunted in weak protest. "you are. you're my little cuddle monster."

"m' all yours," Red murmured sleepily, nuzzling against his sternum.

"you're safe," Sans whispered as he kissed the crack at the top of Red's skull. "you can trust me. i promise. i'll never let anyone hurt you again." He summoned his Soul, letting it bathe his counterpart in emotional security. "i love you."

Red lost himself in the pull from the other's Soul and willingly let it lull him into a semi-conscious state. He mumbled something in response that sounded just enough like a declaration of returned sentiment that it set Sans at ease.

They fell asleep with both their bodies and magics tangled comfortably together.

**Notes for the Chapter:**

> see i warned u


	3. Chapter 3

**Summary for the Chapter:**

> The shell begins to crack...

**Notes for the Chapter:**

> Vague mention of past non-consensual events. Sans has weird fetishes. This whole relationship is strange, who am I kidding.

A few weeks had passed since Red's sudden arrival, and he was coming out of his shell much more quickly than Sans had anticipated. He eagerly accompanied Sans to all of his jobs, keeping him company during long patrol shifts, slurping mustard at the hot-dog station, even tagging along to his weekly stand-up routine for moral support. And Sans enjoyed every single moment of it. The thumbs-up from the back of the audience. The playful banter between sips of condiment. The wonderful, loving, trusting kisses shared under Snowdin Forest's serene flurries.

As for Red? He felt alive. He felt safe and protected and encouraged. Even though he technically already knew all of Snowdin's inhabitants, ever since Sans had introduced him as a visiting cousin, everyone he'd met had treated him like a friend. Not like an annoyance, or a burden, or some disease to be avoided. He felt... less scared. More sure of himself. Nowhere near his brother's level of confidence, but still -- it was an improvement.

He barely even flinched when Papyrus leaned over to kiss the crown of his skull as he dished out a generous helping of spaghetti. And this didn't go unnoticed by Sans, who reached over and rubbed his shoulder affectionately with a big grin.

Red positively beamed, not even needing to hear Sans say it to know his double was proud.

But, as it turned out, Sans said it anyway, once they were in the privacy of what had become their shared bedroom, showering his twin in praise and kisses.

"you're doing so well, red," Sans cooed, cradling the other's skull in his hands and trailing touches of his teeth along his browbone. "i'm so proud of you, babe. you're such a good little boy." The last sentence had slipped out without him actually thinking, and for a moment he wondered if he'd crossed a line -- and then Red arched into him and whined softly, and Sans realized that the line he'd crossed was entirely different from the one he'd thought. "shit, red, did -- did that turn you on?!"

"lil' bit." Red nuzzled affectionately down Sans' neck, giving light, teasing licks to the vertebrae. He was in his element now; he knew exactly how to pleasure another skeleton, especially if it kept earning him words of praise like that. He eased Sans back onto the mattress, his hands going to work under his twin's shirt.

"h-hey, red -- look, this doesn't have to be one-sided, y'know?" Sans tried to sit up, only to be pushed back down.

"s'okay, baby blue," Red purred. "jus' relax. lemme make you feel good."

The petname sent a shiver up Sans' spine, and he lay back and let Red's fingertips dance over his bones, shirt bunched up at his sternum. Red leaned down and tapped his teeth down Sans' ribs, magic sparking with each kiss.

"baby," Sans sighed as Red's phalanges trailed over the crests of his pelvis, making him crane his head back and squirm pleasantly. "fuck, you're really good at this..." His hands ventured down and found Red's shoulders, fingers splaying over the scapulae. Through his growing haze of arousal, he remembered what had set his twin off in the first place. "such a good boy," he breathed lovingly as one hand slid up to cup the back of Red's skull. "s-so good..."

Red nuzzled and keened into Sans' palm, his tentacle-like tongue peeking out from behind pointed teeth to lap eagerly between the metacarpals. The invisible force holding Sans' bones together hummed at the contact from his counterpart's magic. He twirled and tangled the appendage around his fingers like a snake climbing his hand, gently tugging Red's face closer to his own.

"c'mere, loverboy." Sans pulled him into a deep kiss, conjured tongues swirling wetly against each other in the shared cavity of their open mouths. Each tasted slightly spicy to the other: Red's magic was warm, like cinnamon; Sans', cool, more like mint. The tastes mixed and mingled in their saliva, creating a unique flavor unlike anything either had ever experienced. Sans found himself wondering in a brief moment of mental clarity if his other self shared the same thought. "if love has a taste, it's this," he exhaled into Red's mouth.

Red stiffened and sat up, straddling Sans' pelvis, gazing down at him with uncertainty in his eyes. "so this... this is how it feels?" he asked, softly, reverently, sighing as Sans' distal phalanges reached up and trailed down the side of his skull. "being... loved...?"

"maybe." Sans smiled genuinely, the little hearts in his eyes returning; he pushed himself up into a sitting position and curled his arms around Red, still in his lap. "tell me what you feel," he murmured, caressing his spine soothingly.

Red swallowed -- or at least, he imitated the motion as best he could, more out of nervousness than actual necessity. "i... i feel..." His teeth parted, allowing a shaky breath to pass through them (again, an action born from anxiety rather than a real need to breathe). He stared at his hands as he fidgeted with the fabric of Sans' shirt.

Sans tilted his head slightly but said nothing, regarding Red thoughtfully as he continued his gentle, patient strokes. It was a few moments before Red spoke again.

"you're so different from him," he finally whispered, speaking slowly, as though choosing his words carefully. "you don't yell. you don't hit. you... mmnh," he sighed, leaning eagerly into Sans' hand as it curled over his cheek. "when i see his hands coming for me, i panic -- they always claw, or punch, or hold me down." He nuzzled into the other's touch with a soft scrape of bone against bone. "... but you... you reach for me, and i..."

"you come closer." Sans was gently running his hand all over Red's skull now, petting as much of his head as possible.

Red nodded with a little sigh. "a-and when you touch me, i..." He opened his eyes (he wasn't sure when he'd closed them) and found Sans' unoccupied hand, shakily bringing it to rest over his ribcage. "i feel it in my soul." He blushed fiercely. "i... i feel _you_ in my soul," he muttered. "dunno how to explain it. i jus' do."

"no, i understand." Sans kissed Red's forehead lightly. "i feel it, too."

Red's head snapped up to look him in the eye, moving so quickly it popped a few of his vertebrae. "you -- you do?"

"at first i figured i was just relieved to see you again in one piece, cause y'know, you are me, and of course i'd care about another version of me, right?" Sans grinned and shook his head, letting it hang slightly. "heh... i was close, i guess. i mean -- i do care about you, but not just because you're me from another world." He clutched gently at the fabric at Red's ribs. "i have a hunch, but if i'm gonna confirm it, i have to see your soul," he murmured.

Red hesitated for only a second before tugging his shirt off and conjuring his Soul. Its appearance startled Sans: where his was a white inverted heart shape, Red's was, well, red -- though it radiated the same royal blue aura of Integrity. Sans hovered his hand above Red's ribcage, and with a twitch of his fingers, sent a tendril of magic into the glow.

A clear, pure sound resonated within both of them, loud enough to make their bones shiver, yet silent to the rest of the world.

"w-what the fuck was that?!"

"everyone's soul has its own frequency." Sans' smile returned as he withdrew his hand. "i've never met two monsters with the same soul song, even across other worlds..." The glow inside his shirt signaled the manifestation of his own Soul; he took Red's hand and slipped it under the fabric, and as their auras met, the same sound rang within their magic's connection -- as if a slightly different instrument was playing the same chord. "... but you just had to be different, didn't you?"

Red found himself laughing -- truly laughing, with his eyes scrunched closed and his shoulders shaking. "no, you dumbass, i thought the whole point of this was that i'm the same."

"well." Sans joined in with his own giggles. "yep. i walked right into that one."

"hey, he-hey." Red nudged Sans' shoulder. "skeleton walks into a bar. bartender says 'hey, pal, can i get ya anything to drink?' skeleton says, 'nah, the stuff goes right through me!'" He roared with mirth, and Sans doubled over in laughter, smacking the mattress.

"oh my stars, go fuck yourself," Sans sighed fondly, only slightly upset that the mood had been ruined.

"rather fuck you," Red muttered. Their eyes met, both of them blushing heavily.

"isn't that--"

"technically the same thing?" they asked simultaneously, before breaking into another fit of giggles.

"no, but really." Red wiped a stray tear from his eyesocket, still chuckling softly. "i mean, what'd that even be considered? masturbation?"

"selfcest," Sans replied smugly, scooting back and folding his arms behind his head as he leaned against the wall.

"is that even a thing?"

"if it wasn't before, it is now."

The implications of that statement hit Red like an angry Undyne. "are -- are we a 'thing'?" he asked timidly.

"no, you absolute walnut," Sans cackled, reaching over and pawing playfully at his twin. "we're not things. we're people."

Red scoffed and flailed back in retaliation. "oh, fuck you, you knew what i meant!"

"yeah, i did," Sans admitted, slapping weakly at Red's hand for a few moments before catching it in his own and giving it a squeeze. "do you wanna be a thing?" he asked softly. It wasn't a question he posed thoughtlessly -- he'd seen Napstablook and Metatton end up together enough times to know that his fellow monsters would see no wrong in a relationship between Sans and his self-proclaimed cousin. Vaguely, he knew things were different on the surface, even for couples who couldn't reproduce. The surface world was a strange one, where only certain things were considered acceptable. Why did everyone want to be up there so badly? Humans were, from what Sans understood, cruel and judgemental creatures.

"can we?" Red's voice snapped him out of his thoughts. Sans smiled and gave his hand another gentle squeeze, and Red shifted to sit on his femurs.

"in my mind, we already are," Sans murmured. "have been for a while."

Red blushed. "yeah, m-me too." He fidgeted with the hem of Sans' t-shirt. His nervousness didn't go unnoticed.

"you alright?" Sans' brow-bones creased in the center of his forehead.

"y-yeah." Red nodded hastily. "i just, uh." He glanced up sheepishly into Sans' eyes. "i wanna be close to you," he muttered, "b-but..." He hesitated, swallowing, a hand mindlessly tracing a particularly nasty scar on his pelvis.

"... you have a lot of bad memories associated with, uh, intimacy," Sans finished for him, earning a nod and a soft grunt. "and you're not ready to find out what's gonna happen when i try to do the same things he did." Another more enthusiastic nod. Sans hummed in thought as he looked over what he could see of Red's exposed body, making educated assumptions as to his sexual history. Countless scars and scrapes littered his bones, spiderwebbing over the surfaces -- but Red's skull was oddly pristine, save for the large crack on the left side. "did, uh... did he ever do anything to your face?" Sans ventured cautiously.

Red shrugged one shoulder. "forced me to suck him off a few times," he said flatly. Emotionlessly. Blocking it out.

"what about your eyes?"

"my -- eyes?" Red gave his twin a look of utter confusion. "no...?" A spark of excitement ignited in Sans' Soul at the prospect that there was still a way he could make Red feel good that his Papyrus hadn't ruined for him. Red paled slightly as he understood the implication. "whoa whoa whoa, you're not suggesting you're gonna touch me there?!"

Sans swept his thumb across Red's cheekbone. "if you'll let me, yeah," he said softly. When his double's anxious expression didn't fade, Sans gave him a reassuring smile. "it feels really nice if you know what you're doing," he murmured. He brought his hand to his own face and, after dimming his pupil in one eye, gently ran a distal phalanx along the lower rim. He blushed lightly as a shaky moan parted his teeth. "this is actually," he grinned sheepishly and rubbed along the edge with two fingers this time, "one of my favorite places to touch myself..."

Red chuckled nervously. "that good, huh?" Hesitantly, he reached for his own eye socket, but paused when Sans smirked and dropped his hand.

"feels better when someone else does it," he said huskily, cupping Red's cheek. "do you trust me?"

"yeah," Red breathed without hesitation, dimming the light in his right eye.

"relax." Sans traced back and forth just below the opening of Red's socket, simply letting him get completely used to the idea. "if you want me to stop at any point, don't be afraid to say so."

**Notes for the Chapter:**

> EVIL LAUGHTER
> 
> Yeah I ended it there because it was a good stopping point. There'll be more, you filthy fucking sinners.


	4. Chapter 4

**Summary for the Chapter:**

> Skeleton sexytimes! Also more weird Soul bullshit.

"w-wait." Red touched a hand to Sans' chest. "before we, uh -- before we do this..."

"what's up?" Sans pulled his hand away promptly, concern etched on his features.

"n-nothing, i just -- wanted to lie down first."

Sans masked his sigh of relief with a low chuckle. "go for it. make yourself comfortable." As Red lay down on his back, Sans curled up at his side, draping an arm across his shoulders and nudging a skeleton kiss to his cheek.

"alright, go 'head." Red sighed as Sans' fingertips trailed up to his eye socket, just barely grazing the lower edge of the opening. With monsters, intent made up a fairly large percentage of physical interaction -- a fact they both knew all too well -- so if Sans wanted it to feel pleasurable to Red, it would. Or at least, he hoped it would.

The resident Sans watched his double closely as he caressed the lower edge of his eye socket. "you feelin' alright?" His voice caught in his non-existent throat, coming out sounding much more sultry than intended.

"uh huh." Red lifted a hand and lazily stroked Sans' humerus. "s' nice..."

"mmh." Another tap of teeth to Red's cheek as Sans' distal phalanges dipped just a little deeper into his skull. "this okay?"

Red blushed fiercely. "y'don't have to ask that every two seconds," he muttered. "m' not made of glass. you're not gonna break me if you accidentally do somethin' that feels weird."

"yeah, i know." Sans nuzzled against Red's shoulder with the point of his nasal bone. "it's just -- i mean -- you're allowed to change your mind, y'know? just 'cause you consented to this doesn't mean you have to stick with that decision if it gets to be too much for you." He smiled sadly as Red froze as though contemplating this idea for the first time in his life. "i care so much about you," he purred, his fingertips nudging into the magical pressure inside Red's skull. "i want you to want everything that happens between us. i want you to enjoy it with all of your body and soul, not just accept that it's happening." He began to swipe his fingertips back and forth in the dark, suction-like magic of Red's eye, reveling in the soft gasps it drew. "i wanna make you feel fucking incredible..."

"fff-fuck, you are," Red moaned, squirming a bit. Sans glanced down and found that Red had one hand buried down his shorts.

"you're touching yourself," he breathed.

"... y-yeah..."

"i, uh." Sans felt himself blush. "you don't have to, but, uh... can i, maybe, watch?" He cringed as the words left him, expecting Red to freak out or move away. He didn't expect a shrugged, "yeah, okay," followed by Red shimmying his shorts down his femurs. He watched in awe as Red's fingertip traced slow circles around the sensitive cartilage at his pubis, mirroring the motion inside his counterpart's socket.

"fuck, blue, that feels so good," Red whined, his Soul's glow pulsing gently. He scraped a distal phalanx across his pubic symphisis and bucked into his own touch, choking back a cry.

"stars, you're cute." Sans kissed Red's temple as he hooked his fingers in the other's socket and rubbed along the inside of his skull. "oh, baby, i wanna make you feel amazing..."

Red whimpered, rubbing the tender strip of cartilage in earnest now. "s-s-sans," he gasped, trembling; "f-fuck, p-p-please...!" His Soul throbbed eagerly.

"sweetheart, you don't need to ask my permission to cum," Sans murmured against his twin's skull.

"fuuuck, saans...!" With a strangled cry and a final jerk of his hips, Red's Soul burst with the force of his orgasm, erupting with light and swirls of magic that honed in on Sans' chest cavity and brought him to his own climax. Misty blue and red tendrils tangled together, allowing each skeleton to feel for a few moments his own pleasure alongside his counterpart's.

As they lay there panting through the aftershocks of orgasm, Sans gazed into his twin's sockets -- and suddenly, he saw himself through Red's eyes, and he felt Red's Soul screaming the only emotion it could process, 'i love you, i love you, i love you--'

And they both hitched as they felt a gentle tug at their Souls, and--

Oh.

So that was what a Soul Bond felt like.

Red was taken aback when Sans started laughing. "the fuck's so funny?!"

"i just..." Sans sighed and leaned their foreheads together. "i just didn't know that could happen without actually physically mating."

Red fidgeted with his shorts, tugging them back up to his waist. "if mating was the only prerequisite, i'd've been bonded a long time ago," he muttered.

"has to be the right monster." Sans hugged him closer, trying to fend off scary thoughts.

"yeah? too bad we're both left-handed," Red snickered.

 

Their incessant giggling caused Papyrus to chuckle and shake his head as he snuggled into his super-cool race car bed, having just finished cleaning up after dinner. He didn't know the whole story, and he supposed he didn't need to -- both Sanses were happier than he'd ever seen them, and that, in turn, made Papyrus happy.

**Notes for the Chapter:**

> And somewhere in Underfell, Papyrus is like "WHO IS DEFACING MY PROPERTY. I CAN SENSE IT"


	5. Chapter 5

**Summary for the Chapter:**

> a nightmare of what used to be and what could have been.

**Notes for the Chapter:**

> ... i guess i'm venting.

"I love you."

The words came from a younger Boss -- before he'd started calling him Boss -- a blunt-toothed Papyrus with no facial scarring, no Royal Guard outfit, no hunger for dust in his eye sockets. Red leaned into the gentle caress of his brother's bare phalanges on his cheekbone.

"I will always love you, Sans."

Red stiffened. He felt Papyrus leaning in to kiss him -- his eyes were closed; he couldn't force them open -- he knew this couldn't mean anything good, knew how this relationship was going to end up --

\-- he felt a gloved hand close around his throat and slam him down to the floor, and he finally opened his eyes to see the Papyrus he'd come to know. Teeth filed into sharp points, eyes burning with contempt, mouth twisted into a sadistic grin.

"I PROMISE, BROTHER," Boss hissed gleefully, drawing Red's Soul out from his chest. It shattered without any further action from him, splintering into countless shards that faded into nothingness.

Red jolted awake and was suddenly hyperaware of being curled up, back-to-back against Sans. He shuddered and hugged himself, shutting his sockets and willing himself to go back to sleep. Even through the lull of his counterpart's snoring, his self-loathing mind formed thoughts that swirled in his skull and only worked him up further.

_he lied._  
_he said he'd never hurt me._  
_he lied..._  
_of course he did. everyone does._  
_everyone hurts me at some point._  
_... even blue?_

He turned slightly to look over his shoulder at his still-slumbering twin.

_fuck. i wanna trust him, but..._  
_... that'll only make it hurt more, won't it...?_

 

Hopefully no one would notice the tear tracks down his skull in the morning.

**Notes for the Chapter:**

> Did some formatting edits in this chapter.


	6. Chapter 6

**Summary for the Chapter:**

> While Papyrus is away, the boys get a little closer. And then a LOT closer.

**Notes for the Chapter:**

> Yoooo the rating got upped cause of this chapter.

Papyrus was at one of Undyne's Super-Cool Sleepovers, leaving the Sanses alone in the house. It was beginning to feel like a "we can do whatever we want; the parents are out of the house" kind of night, until Red's magic growled in the skeleton equivalent of a stomach gurgle.

"ready to eat something other than pasta?"

"we goin' to grillby's again?" Red looked up curiously from where he lay on the couch with his head in Sans' lap.

"eh, we could." Sans shrugged, continuing to pet the other's skull lazily. "actually, i was kinda thinkin' about cooking something for a change..."

Red pushed himself up on his hands and knees and stared incredulously at Sans. "you can cook?!"

"wh -- of course i can!" Sans broke into a giggle. "i mean, someone had to make sure pap got fed properly after..." He sighed, trailing off, and scratched the back of his head absently. "mmh. you know. ... anyway..."

Red watched Sans quietly as he stood and made his way to the kitchen. After a few moments, he followed suit, finding his counterpart extracting ingredients from the fridge and setting them on the counter.

"things were a little different back home," Red murmured, taking a seat at the table as Sans worked. "my bro and i didn't really have anywhere to go when..." He tugged at the turtleneck of his sweater.

"the core incident?" Sans finished for him.

"y-yeah. that." Red nodded vigorously. "boss and i lived on the streets for a while. had to steal a lot to be able to eat. s' how i learned to survive on condiments, makin' sure he got all of the good stuff to sustain his growing magic."

Sans grinned sadly as he chopped a large mushroom into slices. "sounds like you did the best you could in your situation. i mean, from what you've told me, that universe is pretty fucked, yeah?" He tipped the mushrooms into a pan on the stove; they made a satisfying sizzle upon landing. "honestly, i probably would've done the same thing in your place."

Red crossed his arms on the table and rested his head on them. "i just... i feel like i failed him somehow," he muttered. "i mean -- your papyrus..." He let out a frustrated sigh. "he... actually loves you," he said hoarsely, picking at the table simply to have something to do.

A shiver wracked Sans' spine. He froze where he stood, staring into the pan but not really looking at the mushrooms.

"boss used to love me," Red continued, barely whispering, as if somehow sensing his other self's unvoiced questions. "that's -- that's how i know he doesn't anymore."

Sans recalled the one timeline when he'd confessed to Papyrus and ended up having those feelings reciprocated. He remembered the closeness, the intimacy, the way Papyrus' magic energy had felt -- and he remembered how different his brother's aura had been once the next reset happened. A pang of unease stabbed at his Soul as he noted that Papyrus remembered nothing of his and Sans' brief romance -- but from the way Red spoke, it seemed like his Papyrus _did_ remember. He'd just stopped caring.

"you don't have to go back, you know," Sans said gently, poking at the mushrooms with a wooden spatula before slicing a vegetable a human might describe as a bell pepper crossed with a squash.

"i don't want to." Red buried his face in his arms, yet the position didn't seem to muffle his voice at all. "i don't wanna go anywhere unless it's -- unless it's with you."

"hey. listen." Sans was suddenly seated across from Red, his magic continuing the food prep in his place. "i'm not gonna leave you behind," he murmured, reaching out and squeezing one of Red's hands. "you understand? you're stuck with me, loverboy."

Red lifted his head a little and let out a genuine laugh; a pure, joyous bark of a sound. He then dipped his skull back down, clicking his jagged teeth against the back of Sans' metacarpals. "i don't think there's anyone i'd rather be stuck with."

Sans grinned. "not even jerry?"

"fuck jerry!" Red spat in disgust, jolting up and throwing Sans' hand back at him as though it'd burned him. Sans guffawed heartily, and Red couldn't help but laugh along with him. "don't actually fuck jerry, though," he added hastily as the giggles subsided. As if that really had to be said.

"don'tcha worry, sugar skull," Sans drawled, standing up and pushing his chair in. "that honor's for you, and you alone." He gave a flirty wink before turning to saunter back to the stove.

As Sans continued to cook -- something that appeared to be a blend of vegetables and some sort of bean paste sandwiched between a very flat, round bread -- the kitchen thickened with the dry, static-like sensation of magic coalescing. Red blushed deeply as he realized that he was actually comfortable with the idea of fucking Sans. Not just comfortable, but eager; so eager that his magic had begun to gather in his pelvis, having not quite settled into a form yet. Sans set a plate in front of him, and they ate in awkward silence, neither daring to look at the other.

Once Red had finished his meal (and truth be told, it was damn good, far more palatable than Papyrus' usual cooking), he chanced a glance up at Sans, and cringed upon realizing his counterpart was sporting a blue blush. "s-sorry," he muttered, hunching his shoulders and trying to make himself seem smaller.

"heh. for what?" Sans grinned nervously, twirling his fork on his empty plate. "i mean, i'm the one with, uh --" He cleared his throat. "-- the, uh, problem."

"fuckin' -- !!" Red smacked his palms on the table. "shit, i was worried you were feelin' _my_ magic, but you thought all this was yours, didn't ya?" He gestured vaguely around the room, indicating the thickened aura.

Sans blinked. "lemme guess. you thought the same thing." He smiled and let out a sigh of relief when Red nodded. "hah. imagine that. both of us get horny at the same time and try to hide it from each other."

"well, i mean, i don't see the point in trying to fight it now," Red mumbled huskily, making Sans almost drop the plates he was levitating up into the sink. "i, uh -- i mean, if -- if you, y'know..." He inwardly cursed himself for getting cold feet.

Sans stepped closer and placed a hand on Red's arm. "do... you wanna go upstairs?" he whispered in a way that made his twin shudder.

"fuck, yes..." Red hadn't meant to moan, but once he saw a faint blue glow begin to emanate from within Sans' shorts, he couldn't control his own voice. He hastily stood up and shoved the chair away as they locked in an embrace, teeth clacking in a hungry kiss. When he opened his eyes a few moments later, they were in their bedroom, and Sans was already tugging the hem of his shirt over his head. Seeing his lover's bare ribs made Red suddenly acutely aware of his own clothing, and how much he wanted it off. But with the removal of his turtleneck sweater came the loss of something else he'd grown to be comforted by. "hey -- blue?" He fidgeted nervously with the garment in his hands. "d'you maybe have, uh -- something i could wear around my neck?"

"sure." Sans moved to paw through a drawer, finally extracting a length of red fabric leftover from Papyrus' "armor" creation. "yeah, i noticed you like those sweaters," he grinned, wrapping the makeshift scarf around Red's neck. "guess i'll have to get you a new collar, huh?"

He'd meant it as a joke, but the way the other's eyes lit up made him seriously consider it. "stars, i'd love that," Red murmured reverently.

If Sans had had a stomach, it would have been doing gymnastics. "honestly, babe," he purred as Red let him push him onto the mattress, "how are you so damn cute...?" He swiped his tongue across Red's teeth and felt them part as Red's own slick appendage poked out to draw Sans into his mouth. Sans made quick work of his own shorts, leaving him looming naked over his counterpart. They broke apart after a few passionate moments, a string of saliva stretching and eventually breaking between their tongues.

Red's gaze was drawn to the glowing organ between Sans' femurs: plump outer lips framing delicate darker blue folds, with the tip of an engorged nub peeking out. His magic sent a jolt straight to his pelvis as he realized that Sans was already leaking a semi-opaque fluid. "... damn." Red chuckled sheepishly, finding his voice. "not what i was expecting, but holy shit..."

"yeah, i usually go for the other configuration," Sans grinned, shrugging a shoulder. "it's easier to masturbate with a dick, feels good havin' it stuffed inside something..." He lowered himself onto Red and began to grind lightly against his pelvis. "but i started thinking about riding your cock, having you fill me... and, well, this happened."

"holy fuck..." Red grit his teeth in pleasure as he felt his dick beginning to form under his shorts. "stars, blue, i'd love that."

"yeah?" Sans hooked his phalanges under Red's waistband and gave a gentle, questioning tug. "you really wanna do this?"

Red gazed at him, at his flushed face and gentle demeanor, at the faint white glow within his ribcage that signaled his Soul ready to manifest at any moment. "yeah. i do." His hands joined his twin's, pulling his shorts down his legs, letting his now fully-formed erection spring free. Sans marveled at it, at its ridges and bumps, its curve, its girth, the way it tapered slightly from knot to tip.

"oh, baby," Sans moaned, lowering himself between the other's femurs to get a better look.

"i-is it okay? did i make a good one?"

Sans nuzzled his cheek against it. "it's perfect, sweetheart," he purred. "it's fuckin' gorgeous and i can't wait to feel it inside me."

Red sucked in a breath as Sans slid up his body, nudging his folds around his length and slowly rubbing against him. "i've, uh... i've never actually made a dick before," he admitted quietly.

"could've fooled me."

"i mean, boss is -- you know what he's like. when he's in heat, he wants something to fuck, not get fucked by."

"mmh. don't think about him right now, okay?" Sans kissed a languid trail up Red's jaw, padding his teeth with soft magical constructs that essentially served as lips. "just think about us. right here, right now."

"mmnh..." That wasn't a difficult thing for Red to do. He placed his hands on Sans' iliac crests and gripped lightly, rutting up against him a little more fervently. The heady, musky smell of sexual magic permeated the air, serving to fuel Red's mental images of what his double would look like seated on him, lost in pleasure.

Sans rolled his hips a little differently and Red felt the head of his conjured member become enveloped in warmth; it was a startling difference from Sans' usual cool magic, but not at all unwelcome. "can i?" Sans breathed against Red's teeth, gently curling his phalanges into his ribs.

"gods, please, yes...!" Red gazed up in awe as Sans straightened his spine and began to ease himself down onto Red's cock. He wasn't sure where to look -- Sans' face, contorted with both pain and bliss; his Soul, pulsing rapidly, sending off occasional flares of light; or the site of their joining magic, Red's girth stretching Sans open in a way that didn't look like it felt entirely pleasurable. "doesn't that hurt?" Red managed.

Sans nodded eagerly. "fuck yeah it does," he groaned, his mouth spreading into a smirk. "hurts real fuckin' good..." He began to stroke the soft cartilage where his ribs met his sternum with one hand, the other snaking down his spine to finger the holes in his sacrum. He arched into his own touch, putting on a show for his awestruck lover -- and by the way Red's cock twitched inside him, he was more than enjoying watching Sans caress himself.

"s-stars, you're fuckin' gorgeous..." Red massaged his fingertips into Sans' inner pelvic bone and relished the way his hips shifted, sucking Red even deeper into his heat. Sans let out a breathy moan and rubbed at the base of his enlarged clit as he pressed down as far as he could go, Red's knot nestled comfortably between his folds.

"babe." Sans gazed down with hazy eyes, his magic forming heart shapes within his sockets. "red -- s-sans. you feel so -- so fucking good."

Red stroked his femurs lovingly, his Soul fluttering at the sound of Sans uttering his name -- their name -- the name they only called each other in intimate moments just between the two of them.

Sans rolled his hips languidly, gripping Red's ribs for leverage. "stars, baby, i've wanted this for so long," he moaned, lifting himself off Red just enough that his cockhead tugged at Sans' opening.

Red swallowed unnecessarily and let out something between a moan and a whimper. He felt his gaze drawn to the bright white glow of Sans' Soul inside his ribcage, and with a shuddering sigh, allowed his own to form -- and almost immediately, a tug jerked both skeletons' chests forward as their bond intensified. Wisps of blue and red coiled and tangled between them as Sans lifted and lowered his hips, Red gripping tightly to his iliac crests and thrusting up into him. The room filled with their wanton sounds, the clack of bone against bone, the lewd squelches of physical sex, the hum of magic; and somehow, Red found himself on top of his counterpart, rutting him into the mattress.

"fuck, yes," Sans panted, hearts blooming and swimming in his eyes, mouth hanging open, hands grasping at his lover's bones for something, anything to anchor himself. "oh gods, yes, babe, don't fuckin' stop...!"

Their eyes locked, and a pulse of magic swept through them both, rocking them sensually in a way that their physical joining couldn't compare to. Red slowed his pace somewhat, focusing more on feeding into that connection and feeling it bringing them both closer to their peak. "s-sweetheart," he moaned, grinding his teeth, "can -- can we -- ? t-together...?"

"yeah -- you close, babe?" Sans didn't have to ask; he could feel it in the connection between their Souls, but Red nodded anyway, not minding the verbal reassurance.

"real -- real fuckin' close!"

"if you're gonna cum, do it inside," Sans gasped, reaching down to squeeze at the base of his clit and roll it between his fingertips. A few thrusts more from Red, and his cock swelled at the base as he pushed in one final time, and --

The combined songs of their Souls reverberated in their magic, lashing out and crawling up the walls, entangling on the ceiling, wrapping into and around every crevice and bone in each other's body; and at the same time, physical orgasm surged through both of them, erupting into Sans' constructed entrance and spurting out around Red's length.

Red collapsed heavily on top of Sans, the both of them thoroughly spent. Sans' last thought before he lost consciousness was that humans on the surface may very well have heard their intense climax.

**Notes for the Chapter:**

> Still kinda meh on that ending, but... Eh, whatever.


	7. Chapter 7

**Summary for the Chapter:**

> Things go right. And then, they go wrong. Horribly, horribly wrong.

**Notes for the Chapter:**

> First of all, sorry for taking so long to update!
> 
> Second of all, this chapter doesn't really meet my standards in terms of writing, but it needs to exist, so here ya go.
> 
> This is where the fun begins.

Red had started staying home more often, beginning to feel restless without having any real work to do, so he'd taken up the task of keeping the house tidy. Of course he'd done this back in his own universe, but it felt different now. Here, with Sans and Papyrus, he didn't have to worry about completing specific tasks in a very specific way for fear of being punished. He did what he could, and his housemates made sure to show their appreciation -- which, in turn, pushed Red to do an even better job.

Not only that, but it afforded Sans some time alone, which he needed for a particular reason. The short skeleton gathered some leftover crafting supplies from a drawer (making sure not to wake Red) and stuffed them into his pockets before teleporting to his sentry post. He emptied his pockets onto the wooden surface of his station, measured the circumference of his own cervical vertebrae, and carefully marked a strip of dark crimson leather accordingly.

Recalling Red's face when he'd offered to get him a new collar, Sans felt his Soul thrum with Determination.

x

Red stood with hands out and eyes closed, having been instructed by his twin to do so (and not to peek -- which was easy, considering they'd just eaten dinner and his eyelids were feeling pleasantly heavy). He felt a weight in his hands, a familiar material; heard the soft jingle of metal on metal. Stunned, he gazed down at the object in his grasp: dark red leather, rounded gold studs, a small tag engraved with symbols that Red knew to be Wingdings. 'Sans.' Was that a name tag, or a declaration of ownership...?

Trembling slightly, he shoved the collar back into his double's hands and dropped to his hands and knees before him, sticking out his neck. Sans understood immediately, kneeling to fasten the collar around Red's neck. His hands gently nudged Red's chin, tilting his skull up for a light kiss.

"how's it feel?" Sans' browbones creased in concern. "does it fit alright? it's not too tight, is it?"

"it's perfect. it feels like -- like home." The word was almost foreign to Red, reminding him of his origin universe. "at least, it -- it feels like what i think home should feel like."

Sans gave a small "mm" of understanding and simply sat there admiring the way the collar looked on the other. He'd done a pretty damn good job on it, if he did say so himself.

Magic began to build and envelop Red, and Sans felt the panic from his counterpart's Soul stab directly into his own. "what's going on?"

"i don't kn-" was all Red managed to get out before he felt himself sucked through the Void against his will.

Sans fruitlessly pawed at the air where Red had just been, his magic flaring inside of him with the force of his emotion. He let out a feral roar that rattled his bones with rage.

"SANS?" Two knocks and one squeal of a cranky hinge later, Papyrus stuck his head into the room. "WHAT'S GOING ON? IS EVERYTHING ALRIGHT?"

"I have to go somewhere," Sans said as calmly as he could manage, digging through various articles of clothing strewn about.

"WHERE ARE YOU GOING? AND... WHERE IS RED?"

"Dunno." Sans shivered as he lay his hands on Red's well-worn leather jacket. "Something's not right, Pap. I feel it in my Soul." He shrugged the jacket on and inhaled the lingering scent in the fur-lined hood, his Soul reaching out through the magic connecting him and his alternate self, feeling for a sign of his lover.

Papyrus nodded in understanding. "Please be careful, brother." He smiled warmly when Sans flashed him a grin and a thumbs-up.

 

And then everything

 

went quiet  
and cold  
and dark.


	8. Chapter 8

**Summary for the Chapter:**

> Things go horribly wrong. And then they kinda start to go right again.

**Notes for the Chapter:**

>  **WARNING -- This chapter contains depictions of an unhealthy relationship.** The paragraphs between "xx" dividers depict a physically and mentally abusive scene that also borders on rape/non-con. Please be careful while reading.

Sans gasped as he finally exited the Void, falling to his hands and knees on a cold, hard floor. Dark spots swam in his vision and static buzzed in his nonexistant ears from the force of the sudden and unexpected teleportation. Just as he was about to sit up and get a good look at his surroundings, something grabbed the back of his collar and roughly yanked him to his feet -- or rather, dangled him in the air so that the toes of his sneakers barely brushed the floor.

And Sans found himself staring into the sharp, scarred face of his younger brother.

Papyrus' sockets narrowed briefly as he eyed Sans up and down. "EXCELLENT WORK, DOCTOR," he rasped, sparing a glance to Alphys beside a large machine of some sort -- Sans didn't have enough time to get a proper look at it before he was being dragged away behind a very satisfied Papyrus. He stumbled along, tripping over himself in an effort to keep up with the other's stride.

He didn't know what to do -- didn't know what he _could_ do. His mind shut down as Papyrus led him through Hotland, gripping his collar tightly. He ducked his head shamefully and fell back into their old routine. As they made their way through Waterfall, the pink Echo Flowers snickered and giggled disparagingly as Papyrus stalked past with his brother in tow. Sans shuddered and tried to ignore them, but their jeering only seemed to get louder, patronizing him, mocking his vulnerability, his weakness... He was almost thankful for the sudden chill that signaled the entrance to Snowdin.

Almost.

Papyrus shoved Sans into the house, slamming the door none-too-gently after stepping in behind him. Sans didn't dare move. He stood there, shivering more and more with the sound of each consecutive lock.

"Sans." Papyrus' voice was sickeningly, deceptively, gentle. "Where have you been."

"n-n-nowhere, boss." Sans stood completely frozen but for the audible shuddering of his bones. "j-jus' got stuck in another timeline an' couldn't get back--"

"Turn and face me when you address me."

Sans yelped and spun around practically instantly, hunched in fear, unable to meet Papyrus' gaze. "i-it was jus' a -- a sh-shortcut gone wrong, boss--"

"Indeed." Papyrus stared coldly down his nasal bone before taking a step toward him with his significantly longer legs. "Perhaps you'd care to explain _this,_ then?" He snatched Sans' collar, tugging him forward in a way that wasn't particularly comfortable.

"a-ah -- that's just, uh--" Sans' pupils darted around nervously as he searched for an explanation. "m-my old one, uh -- i-it got, um -- d-destroyed?" Well, it wasn't exactly a lie. Blue had made damn sure to obliterate the thing.

"Sans, I don't think you're being truthful with me." Papyrus stepped forward again, crowding Sans and forcing him to shuffle backwards. "I don't much appreciate that." He continued until he'd backed Sans up against a wall. "This isn't how I _trained_ you, whelp," he hissed.

Sans flinched. "s-s-sorry, b-boss," he whimpered.

**xx**

The last of Papyrus' restraint snapped. "NOT YET, YOU'RE NOT," he snarled, reeling his hand back; his eyesocket flashed a brilliant red as a bone construct appeared in his hand and consequently smacked Sans across the face. The yelp it produced brought a twisted smile to Papyrus' jagged teeth. "Good boy," he purred, tenderly stroking the afflicted area with a gloved hand.

Sans hated himself for the way he instinctively nuzzled into the touch.

"That's right," Papyrus cooed. "Now... Be a good little pet and scream some more for Boss, won't you?" With no further warning, he dropped to his knees, slamming his head down with a _**CRACK**_ that could have been either the floorboards or Sans' skull. "Beautiful," he growled as Sans let out a cry of mixed surprise and pain. "I thought I might have to discipline you more than this to make you remember... But you're doing such a good job." He sat Sans up and caressed his skull, delighting in the fragments of dust that clung to his fingers. "You're so eager to please, aren't you?"

"uh huh," Sans gasped, turning his face into Boss' hand, rubbing his teeth against the worn red leather.

"You'd damn well better be." Papyrus summoned another bone and clocked him with a backhand swing this time. He savored Sans' whimpers for a moment before leaning over him. "Now tell me," he said, his voice low and gravelly, reverberating in Sans' skull. "Tell me who you belong to."

"y-you, boss," Sans squeaked, rewarded by Papyrus pushing him onto his hands and knees.

"Good." Papyrus pressed his pelvis against Sans' backside, causing him to shudder. "Are you going to leave me again?"

"n-n-no, boss..." Sans choked on his own breath as Papyrus yanked his shorts down and exposed his tailbone. "n-never, i p-promise...!"

"That's my good little slut," Papyrus drawled, fingers rubbing at Sans' pelvic bone. "I take it you know what to do now, hmm?"

Sans nodded frantically. "uh huh..." He swallowed at the jingle of Papyrus' belt buckle and the growl of a zipper.

"Good boy." Papyrus gripped the back of Sans' head and bashed his face down against the floor. "Show me you know who owns you," he hissed, his hot magic rubbing against the coalescing aura at Sans' tailbone. "Show me that you know who your fucking Boss is."

**xx**

"oh, so _you're_ the boss around here!" A third voice, though somehow not unfamiliar, startled Papyrus from acting any further. "well, mr. boss, i'd like to file a complaint." Several hard objects pelted him in the side of the head, knocking him away from Sans, who hastily pulled his shorts back up before scrambling to put as much distance as he could between himself and his brother.

Fuming, Papyrus dismissed his conjured organ and fixed his clothing, turning to locate his assailant. There stood Blue, left hand outstretched lazily, eye blazing with Justice and Integrity.

Blue glanced down at Sans, who had just positioned himself behind his twin's legs. He cringed at the injuries to his skull. "you hurt him?" he asked Papyrus, jerking his head in Sans' direction.

Papyrus bristled, sneering, "I am at liberty to do what I wish with my property."

"dude." Blue quirked a brow-ridge at him as he shed the fur-lined jacket and kneeled to drape it over Sans' shoulders. "you can't just 'own' a person. they're not things." He dug around in his hoodie pocket and pulled out some sort of pastry, which he handed to Sans, who voraciously consumed it.

"You obviously don't know how things work around here," Papyrus scoffed, thrusting out his hand to fling half a dozen bone spears. A wall of white bones jutted up from the floor to shield the two from the attack. Papyrus grit his teeth -- the bastard hadn't even been looking!

"nah, he's told me enough." Blue grinned fondly at Sans before getting to his feet and facing Papyrus again with a much colder expression. "speaking of, you wanna tell me how you dragged him back into this hellhole?"

"Doctor Alphys built a machine that tracked down his Soul signature and transported him back," Papyrus explained, as if this was both a waste of his time and too complicated for him to fully understand. "I didn't concern myself with the details."

"yeah, you wouldn't, would you," Sans muttered.

"WHAT WAS THAT, WHELP?!"

"n-nothing, boss!" Sans squeaked and dove behind Blue's legs again.

"hey, it's okay, you're alright," Blue murmured, reaching down to stroke Sans' skull lightly. "don't worry. he can't hurt you anymore. I won't let him," he said darkly, turning his empty sockets on Papyrus.

**Notes for the Chapter:**

> If you skipped the selected paragraphs, here's a summary:
> 
> UF!Papyrus beats on UF!Sans (who's still too afraid of him to fight back) and tries to stick his dick in him. That's basically it.


End file.
